According to the researchers, every year in bed men produce about 26 gallons of sweat. On hot days, wet sheets becomes a suitable environment for the growth and reproduction of microorganisms. Feather and synthetic pillows that are used for 1.5-20 years, contain from four to 17 species of fungi.

Among the microorganisms living in bed, can include not only those fungi that live on the human body, but those that get there with pollen, animal dander, dust particles and soil. In just a week the number of microorganisms becomes high enough to cause allergic reactions in humans. Symptoms can include a sore throat, asthma attacks and sneezing.

Experts suggest at least once a week to wash bedding that will avoid the negative health consequences.